KANSAS CITY, MO. — By the time she heard the public address announcer call her name, it may be that the only person surprised was Allyssa Brubeck herself.

So there she was last Friday night, the new homecoming queen, a 19-year-old with Down syndrome, jumping and jumping under the football stadium lights as the full crowd from Park Hill South High School in Kansas City cheered and cried.

And perhaps the best part of the whole experience, say some of the adults who watched it unfold, is that all those high school teenagers behind the Allyssa-for-Homecoming-Queen phenomenon don’t seem to understand what all the outside attention is about.

They certainly understood Allyssa’s popularity in the school she has attended all four years. Always smiling. Always hugging.

“She deserved to be homecoming queen,” said Sam Boling, 17, who was a runner-up for queen.

But the school’s journalists reporting the outcome had to be persuaded by their teacher that Allyssa’s disability might be worth a larger story on its own.

The students are a bit perplexed that the district’s posting of the story on its Facebook page with Allyssa’s picture went rocketing across the internet. The number of “likes” was approaching 1,500 in the first 24 hours of the posting. The number of hits as it was being shared passed 10,000. Nothing on the district’s page had drawn anywhere near that much attention before.

The nominating process for queen began about three weeks ago. Seniors could write down five names and the top five would be the nominees.

Allyssa was one of the five.

“I thought, ‘That’s nice, that’s sweet,’ ” Cindy Small said.

It was a wonderful gesture, so she thought.

But when the final voting was underway, students began to feel the swell of support for Allyssa. By the time the nominees were introduced at the Friday pep rally in the gymnasium, the movement was overwhelming. It came out in the roar the students unleashed when her name was called.

Leah remembered her first year of cheerleading, trembling on a cold night without ear muffs or gloves. Allyssa cupped her gloved hands around Leah’s ears and offered Leah her scarf.

Her sister, who has grown up with her the past six years, sees the same generosity with everyone Allyssa meets.

“She does not know a stranger in the world,” Annabelle said.

And, said Cindy Small, Allyssa is “fearless.”

Whatever Annabelle did, Allyssa would do, too — golfing, swimming, biking. Allyssa wanted to be a cheerleader, so she went out for the team and got on. Her parents let her cheer at home games that first year, but held off letting her travel on the team bus to road games.

“We were not ready,” Small said. “She was.”

The next year she was travelling, keeping in touch with her cellphone.

The Down Syndrome Guild of Greater Kansas City put a picture of Allyssa in her uniform on a billboard on Interstate 29 with a message asking the question: How do you treat someone with disabilities? Like anyone else.

All along the way she was blending in with the Park Hill South students. It was, to them, the natural way.

School systems have come a long way over the past generation in including children with disabilities in their general classrooms and programs, said Amy Allison, executive director of the Down Syndrome Guild.

“They’re growing up together,” she said. The fear and intolerance of the past are falling away and disabilities among classmates “are negligible to kids,” she said. “They see the challenges they face, but they see they are happy and they want to help.”

It all played out Friday night when the homecoming court took the football field at halftime, waiting for the announcement. The crowd began chanting, “Allyssa! Allyssa! Allyssa!”

Sam said she wanted Allyssa to win. She expected her to win.

Allyssa’s reaction — genuine surprise and joy — brought out the biggest cheer yet. Sam was crying, worried that people might think she was upset at having lost. She ran and gave Allyssa a hug.

“I was so happy she won,” she said.

Her parents stood at either side, with the old fears so far gone, feeling “just joy,” Cindy Small said. “It was incredible.”

There would be the Saturday parade, riding in a green convertible. And the coronation dance Saturday night.

And then came the tides of well-wishers and journalists with all their cameras.

Wednesday afternoon, while others were taking a break, Allyssa had her own camera out, stopping schoolmates, snapping pictures.

“Hey,” she said to a trio of football players passing by toward practice, “can I get your picture?”